The discovery of H. pylori's role in peptic ulcer disease offers an opportunity to successfully treat millions of people who until recently were assumed to have a life long problem. It is possible to permanently cure ulcers by eradicating H. pylori infection. However, this bacteria is difficult to eradicate. The significant failure rate of current therapies requires physicians to test 20% or more of treated patients exhibiting recurring symptoms. The benefits of eradication in terms of quality of life and reduction in medical care costs are monumental. Our objective is to market a test that will allow physicians to easily determine the effectiveness of eradication treatment. MSI has developed a simple, single sample blood test to determine the presence of active H. pylori infection based on the bacteria's urease activity to split urea to carbon dioxide. A small dose of 13C -urea is administered and if the bacteria is present, 13 CO2 is detected in blood. A blood-based test is quicker, more accurate, less expensive, and familiar to the medical community than other competing diagnostic tests. In Phase II, we will conduct the validation studies required for FDA clearance. The test will be the first FDA approved product for this indication. Proposed commercial applications: There are millions of Americans with peptic ulcer disease being treated for H. pylori infection. In this group, 20% or more will require post treatment evaluation. The proposed test because of its low cost, accuracy and convenience will be the best method to determine the effectiveness of the treatment.